Rapid discharge hopper car



June 8, 1965 R. c. ORTNER 3,187,684

RAPID DISCHARGE HOPPER CAR Filed March e. 1961 5 Sheets-Sheet 1 INVENTOR. ROBERT C. 02mm,

ATTORNEYS- June 8, 1965 R. c. ORTNER 3,187,684

RAPID DISCHARGE HOPPER CAR Filed March 6. 1961 5 Sheets-Sheet 2 Q ,5 Fig.5 4/ & INVENTOR.

3 ROBERT C. ORTNER, mgwww a ATTORNEYS.

June 8, 1965 R. c. ORTNER RAPID DISCHARGE HOPPER CAR 5 Sheets-Sheet 3 Filed March 6. 1961 2; 5b 2 0 b 6 25 Fig.8

INVENTOR. 205521" C. OR'ruER,

ATTORNEY.

June 1965 R. c. ORTNER 3,187,584

RAPID DISCHARGE HOPPER CAR Filed March 6. 1961 Y 5 Sheets-Sheet 4 IINVENTOR. ROBERT LCLORTNEz,

ATTORNEY' United States Patent O 3,187,684 RAPE) DISCHARGE HOPPER CAR Robert C. Ortner, Cincinnati, Ohio, assignor to Ortner Freight Car Company, a corporation of Kentucky Filed Mar. 6, 1961, Ser. No. 93,529 4 Claims. (Cl. 105-248) This invention relates to railway cars, and has to do more particularly with freight cars of the type wherein the load is discharged through doors in the underside of the car body. Such cars are generally known as hopper cars, and heretofore various forms and arrangements of discharge openings have been proposed by means of which the contents of the car can be discharged. The most common type of hopper car in use today is provided with spaced apart chutes terminating in hinged doors, there being a single door for each chute arranged to be opened by the manual disengagement of latch means, such as a hook type, at each end of the door. To unload the car it is necessary for the yardman or crew members to walk along each side of the car and manually release each of the latches, thereby freeing the doors for opening movement, the doors being opened under the force of the contents of the car. When the load has been discharged, it is then necessary to manually reclose andrelatch each of the doors.

Conventional hopper cars of the type just characterized, in addition to requiring manual opening and reclosing of each hopper door present additional problems in that it is often difficult to obtain complete discharge of the contents, particularly where materials uch as pulverized coal, wood chips and the like have been compacted by the motion of the car, and/ or exposed to the elements during transit and subsequently frozen or caked. Under such circumstances it is literally impossible to clear the conventional car simply by opening the doors; and it is often necessary for the crews to use picks and shovels or vibrators or car shakers to loosen the material so that it will flow from the chutes. Where coal has been frozen in a conventional hopper car, it is not uncommon for the crew to build fires under the chutes to loosen the frozen material, but oftentimes such measures result in considerable damage :to the underside of the car and the air brake system.

Accordingly, a principal object of the instant invention is the provision of an improved hopper type car construction which eliminates the diihculties enumerated above, the bottom of the car comprising essentially a continuous set of door openings capable of completely discharging the contents of the car rapidly and completely even under adverse conditions.

A further object of the instant invention is the provision of a hopper car construction wherein the entire car body comprises essentially a single hopper closed across its bottom by coacting pairs of hopper doors arranged crosswise of the car throughout the effective length thereof, the sets of doors, when open, defining in effect a single discharge orifice interrupted only by bracing members of minimal size which act to assist in discharging the load as it drops upon the opening of the doors, rather than obstructing the discharging of the load as is the case in conventional hopper cars.

A further object of the instant invention is the provision of improved means for opening and closing the pairs of hopper doors, such means acting to securely lock the doors in the closed position and yet readily release them in an essentially automatic operation when it is desired to discharge the load.

Still a further object of the instant invention is the'provision of an improved hopper car of the character described wherein the door controlling mechanism for the entire car may be actuated from a single station, either automatically or manually, and after discharge of the load, the same control mechanism may be utilized to recl-ose all of the doors, thereby eliminating the necessity for one or more crewmen to manually and individually open and close the several hopper doors.

Still a further object of the instant invention is the provision of door actuating mechanism of the character describe-d wherein the mechanism may be arranged to sequentially open the several sets of doors progressing from one end of the car to the other, all in .a continuous op ration, thereby permitting the car to be unloaded while in continuous movement, as where it would be moved along on a trestle or other track arrangement overlying'a receiving station for the material. 7

Yet another object of the instant invention is the provision of'door actuating mechanism of the character described which is of sturdy and yet simple construction, and which embodies safety features which will guard against malfunction of the device and possible accidental release of the hopper doors.

The foregoing, together with other objects of the invention which will appear hereinafter or which will be apparent to the skilled worker in the art upon the reading of these specificationgl accomplish by that construction and arrangement of parts of which I shall now describe an exemplary embodiment.

Reference is now made to the accompanying drawings wherein:

FIGURE 1 is a diagrammatic side elevational view of a hopper car in accordance with the instant invention.

FIGURE 2 is an enlarged fragmentary perspective view with parts broken away to illustrate hopper door actuating mechanism in accordance with the instant invention.

FIGURE 3 is an enlarged fragmentary sectional view taken along the line 33 of FIGURE 2 illustrating the actuating mechanism for the hopper doors.

FIGURE 4 is a sectional view taken along the line 4-4 of FIGURE 2 illustrating the mechanism for opening and closing the hopper doors.

FIGURE 5 is a fragmentary sectional view similar to FIGURE 4 but illustrating the hopper doors in the open position.

FIGURE 6 is an enlarged fragmentary sectional view similar to FIGURE 5 with the hopper doors in the closed position and showing the sealing means along their free side edges.

FIGURE 7 is a fragmentary diagrammatic side elevational view illustrating the linkage means for opening and closing the various sets of hopper doors.

FIGURE 8 is also a fragmentary diagrammatic side elevational View illustrating the sequential operation of the actuating mechanism for opening and closing the hopper doors.

FIGURE 9 is a vertical sectional view taken along the line 99 of FIGURE 8.

FIGURE 10 is a vertical sectional view taken along the line Iii-14; of FIGURE 8.

FIGURE 11 is a fragmentary perspective view of one end of a hopper car in accordance withthe instant invention.

FIGURE 12 is a fragmentary plan view of one end of a hopper car showing the invention applied to a car having a full length center sill.

FIGURE 13 is a sectional view taken along the line 13-43 of FIGURE 12.

Referring first to FIGURE 1 of the drawings, I have therein illustrated a hopper car comprising a body I mounted on conventional trucks 2, and it will be understood that the car body will have vertically disposed side walls terminating at their ends in inclined end walls or slope sheets 3 which terminate downwardly in a rec tangular discharge opening 4 extending the full length of the car body between the lowermost ends of the slope sheets 3. In accordance with the instant invention, the discharge opening is adapted to be closed by sets of hopper doors 5a and 5b arranged in coacting pairs of hopper doors lying in side-by-side relation, together with additional doors 5c and 5d at the opposite ends of the discharge opening, the hopper doors being hingedly connected to transversely disposed door supporting members 6 extending between the side sills '7 which form 'a supporting frame for the side walls of the car. As will be evident from FIGURE 1, the side walls of the car terminate downwardly in triangular projections 23 which coact with the sets of hoppendoors to close the sides of discharge opening 4. It will be evident, however, that when the sets of hopper doors are moved to the open position, which is indicated in dotted lines, the entire bottom of the car will be effectively opened so that the material con .tained therein may be discharged. While the expanse of the opening 4 is broken by the transverse door supporting members 5 and, in one embodiment of the invention, by a continuous center sill, these members comprise relatively minor obstructions as compared to the over-all dimensions of the opening 4 and do not impede the un- ,loading'of the contents. In fact, and as will be pointed out in greater detail hereinafter, by providing the door supporting members and the center sill, if. one is employed, with inclined upper edges, these members tend to assist in discharging the load in that they act as wedges tending'to break up the load as it seeks to pass through the discharge opening under its own weight. The effectiveness of the construction was demonstrated in recent tests wherein a car constructed in accordance with the instant invention and containing sixty-seven (67) tons of pulverized coal /4 inch x 28 mesh) was discharged from the car in a total time of twelve (12) seconds. Similarly, a sixty-eight (68) ton load of frozen fine coal (1% inch X 28 mesh) was completely unloaded in twenty seconds.

In order to effect such rapid evacuation of the hopper car, it is necessary to provide means which will rapidly and efiiciently open the hopper doors, and to this end 1 provide the improved form of door actuating means the general organization of which will be seen in FIGURE 2. Referring to this figure, it will be seen that the oppositely directed doors 5a and 5b are provided with hinges 9 which, it will be understood, are secured to the transverse turn being pivotally connected to the hopper doors Sb'and 5a, respectively, by means of ears 14.

The closed or locked position of the oppositely directed pair of doors is seen in FIGURE 4, and it will be noted that in this position the pivot point 15 between bell crank 11 and link 12 lies beyond dead center of the linkage, as represented by the line 16, so that the door 5b is effectively locked in the closed position'and the weight of the door- 5b: and the load pressing thereagainst acts to maintain the linkage in the closed and locked position. Preferably, a stop 17 is provided to establish the fully closed position of the parts. While it is true that the pivot point 18 between the bell crank and link 13 lies below the center line 19, this position is also past dead center, bearing in mind the opposite direction of rotation of the door 5a;

hence the .same elfectis achieved with respect to the door 5a. However, by rotating the rock shaft 10 and the bell crank 11 in a counterclockwise direction, the doors will be released and the parts will assume the position illustrated in FIGURE 5, which is the full open position of the hopper doors. It will be readily apparent. that'by subsequently rotating the rock shaft 10 in-a clockwise 'dead center and the door 50 will be free to open.

direction, the hopper doors will be returned to the closed position and relocked.

It will be understood that the locking unit just described will be provided between each adjacent pair of hopper doors, as illustrated in FIGURE 7, and preferably each of the rock shafts 10 will mount a pair of the bell cranks '11 and the associated linkage spaced apart laterally of the car so' as to contact and support each half of the doors. The endmost doors Sc-and 5d do not have opposing counterparts, but rather they are each actuated by a rock shaft 19 and a bel crank, although depending upon which end of the car is involved, one arm of the bell crank in the associated linkage may be eliminated. Thus, with reference to FIGURE 7, the leftmost door 50 will be controlled by the bell crank 11a which is connected to the door 50 by the link 15a, which is identical to the links 13, but in this instance the opposing arm of the bell crank may be shortened to define a stop engaging projection 11b which contacts stop 17a. Otherwise the operation of the bell crank 11a will be identical to the operation of the bell cranks 11, i.e., when the shaft 10 is rotated in a counterclockwise direction, the link 13a will be moved beyond In similar fashion the door 5d at the opposite ends of the car will be opened by the bell crank which in this instance may consist solely of the arm 11d operatively connected to the door 5d by means of link 12a. It should be readily apparent that the series of rock shafts 10 controlling the sets of doors 5a, 5b and the individual doors 5c and 5d could be manually actuated from either side I of the car, as by means of crank arms or hand wheels,

I of the rock shafts 10 with a lever arm 20 operatively connected to one end of a link member 21 the opposite end of which is pivotally connected to an ear 22 fixedly secured to an elongated actuating bar 23, which may be in the form of an I beam extending lengthwise of the car 'body and slidably journaled either to the center sill of the car or, in the event the car does not contain a center sill, to one of the side sills thereof. Thus, as seen in FIGURE 2, the actuating bar 23 may be slidably supported by means of brackets 24 welded or otherwise bar 23 in the direction of movement of the arrow acts to move the linkage 21 from the position illustrated in solid lines, in which position the rightmost end of elongated slot 25 is in contact with the pin 26, to'the position illustrated in dotted lines at 21a, in which position the leftmost end of slot 25 contacts pin 26 and the link 21 acts to movethe lever arm 20 in a counterclockwise di rection, therebyrotating rock shaft 10. The lever arm and rock shaft need only'be rotated a distance sufiicient to move the pivot point between the bell crank 11 and link 12 beyond the center line 16, whereupon the force exerted by the hopper door 5b will move the locking unit to the open position, and in so doing the lever arm 20 and link member 21 will be moved to the position illustrated at 21b. This arrangement not only prevents back lash of the rock shaft, but in addition the elongated slots 25 permit relative adjustments between the link members 21 actuating successive sets of doors so that by altering their relative positions along the actuating bar 24, i.e. the points at which the link members 21 are secured to the actuating bar, the successive sets of doors can be sequentially opened. That is, the pairs of doors can be made 'to open in sequence, as where the car being unloaded is continuously moved over a loading station and the move- I ment of the actuating bar initiated as the leading end of the car approaches the unloading station. Such sequential opening of the doors is illustrated in FIGURE 8 wherein it will be seen that the link member 21a having slot 25a of the leftmost assembly-which controls the door 5chas already nipped the lever arm 20, whereas the leftmost end of the slot 25b in linkage member 21b has not yet contacted the pin 26. The leftmost end of the slot 250 in linkage member 21c is even further removed from the pin 26, and the leftmost end of the slot 25d in linkage member 21d is even further removed. It will be apparent, however, that such arrangement will permit the sequential opening of the various doors.

The movement of the actuating bar may be effected in numerous ways. Exemplary actuating mechanism is illustrated in FIGURES 2 and 3 wherein the actuating bar 23 is provided with a rack 27 the teeth of which engage a gear 28 mounted on a shaft 29 journaled beneath the car body, the shaft 29 projecting to the side of the car where it mounts an actuating wheel 34). The wheel 30 may be in the form of a hand Wheel which may be manually turned to move the actuating bar; or the wheel 30 may be provided with a rubber tire and positioned to contact a rail or track 31 at the unloading station, the track 31 being of a length such that it will be contacted by the wheel 30 as the car moves to unloading position and rotate the shaft until the actuating bar has been moved to the fully opened position. Similar means may then be provided to rotate the wheel in the opposite direction to reclose the hopper doors subsequent to the unloading of the car. Alternatively, the movement of the actuating bar may be initiated by a hydraulic or pneumatic cylinder under the manual control of an operator, or the control means for such cylinder could be arranged to be actuated as the car moves onto the unloading station, Alternatively, the actuating bar could be actuated through suitable gearing connected to a prime mover, such as an electric motor or the like.

I also prefer to provide the actuating mechanism for each set of doors with a safety stop to prevent accidental opening of the doors in the event of breakage of the link member 21. Thus, referring again to FIGURES 2 and 3, it will be seen that the lever arm 20 is provided with a shoulder 32 which, when the lever arm is in the closed or locked position, is contacted by the stop member 33 pivotally secured to the car body or other support. It will be evident that this stop member will prevent counterclockwise or opening movement of the lever arm 20. However, when the actuating bar 23 is moved, the stop member 33 will be pivoted to inoperative position by means of a lug 34 which swings the stop 33 upwardly, thereby permitting the lever arm 20 to move in a counterclockwise direction, the parts thus assuming the position illustrated in dotted lines in FIGURE 3. When the actuating bar is subsequently returned to the closed or locked position, the pivoted stop 33 will return to its position overlying the shoulder 32.

As has already been indicated, the instant invention is applicable both to cars having full length center sills and also to cars in which the center sill has been eliminated in the area of the discharge opening 4. A car of the latter character is illustrated in FIGURE 11 wherein the center sill section 34a terminates adjacent the endmost hopper door 50. Where such center sill sections are employed, the weight load of the car is transferred to the side sills 7 by means of horizontally disposed transfer plates 35 at the ends of the car. In such cars, the transverse door supporting member 6 may be additionally reinforced by supporting ribs 36 extending upwardly between the transverse members 6 and the vertical supports 37 which extend upwardly from the side sills 7 and reinforce and support the plates 38 defining the side walls of the car. Preferably, the rib members 36 will be of tubular construction, being elliptical in cross section so as to provide added strength and yet minimize obstructions within the car body.

It also may be pointed out at this juncture that the car end walls, which are composed primarily of the slope sheets 3, are preferably inclined at an angle of about 40 to 60 from the horizontal, depending upon the characteristics of the materials to be handled in the car, it having been determined that such inclination is particularly effective in inducing rapid evacuation of the car. It has been also found highly desirable to either form the slope sheets 3 from stainless steel or provide them with a stainless steel covering, indicated at 39. Such surface finish for the slope sheets permits the con: tents to more readily slide toward the hopper doors.

In keepingwith the concept of freeing the interior of the car body from obstructions which would tend to cause the contents of the car to cling or arch, thereby impeding its discharge, the side walls of the car may be provided adjacent their lower ends with inclined plates 40 arranged to overlie the side sills 7 and hence direct the contents downwardly through the discharge opening. Similarly, and as will be readily seen in FIG- URES 6 and 11, the construction of the transverse door supporting members 6 is such that they have inclined upper surfaces which define angle plates 40a the opposite side edges of which overlie the uppermost edges of the hopper doors 5a and 5b. FIGURE 6 also serves to illustrate a preferred arrangement for sealing the free side edges of the hopper doors along their lines 'of contact. Thus, the hopper doors terminate in down turned flanges 41 and 42 to which strips of gasket material 43 and 44 are secured; and it will be evident that when the sets of doors are in the closed position, the strips of gasket materials will be juxtaposed, thereby effectively sealing the doors. Along their opposite end edges, the hopper doors may be provided with upturned flanges 45 which engage about the triangular projections 8 to effect an essentially sift-proof condition along the opposite side edges of the car body. It will be understood, of course, that overlapping flanges may be employed along the free side edges of the hoppers in place of the flanges 41, 42, if so desired.

Referring now to FIGURES 12 and 13 of the draw ings, I have therein illustrated the invention as applied to a car having a full length center sill 46. In such event, the center sill is provided with a. hood 47 having inclined Wall surfaces tapering outwardly and downwardly from a ridge 47a extending lengthwise of the car and joining at its opposite ends with the slope sheets 3. The hood thus serves to direct the contents of the car outwardly and downwardly through the hopper doors which, in this instance, will be divided into two parts, such as the parts 48a, 48b and 49a, 49b lying on opposite sides of the center sill, the door parts 48a and 48b, for example, terminatinginwardly beneath the hood 7 47 and just short of the center sill. It will be understood, of course, that the hood 47 may terminate downwardly in triangular portions 50 corresponding to the triangular projections 8 at the outer ends of the door sections, thereby effectively closing the discharge opening. Supporting ribs 36a in the form of flat plates extend upwardly and outwardly from the center sill 46 to the vertical side wall supports 37. Preferably, the door sections 48a, 48b will be joined together beneath the,

center sill by means of a transverse frame member 52 which acts to secure the door sections together for joint movement. It will be understood, of course, that each of the door sections will be provided with one or more of the bell crank and link locking members jointly actuated from a rock shaft underlying the transverse door supporting members 6.

Where the car is provided with a continuous center still, such as the sill 46, I prefer to mount the actuating bar to the center sill in the manner illustrated in FIGURES 8, 9 and 10 wherein, for purposes of simplicity, like parts have been given like reference numerals. In such event, the wheel 30 which is used to effect axial movement of the actuating bar 23, may

be arranged to contact a track section 31a mounted along side the rails along which the car moves; and if desired such track section 31a may be provided with pneumatic or other forms of raising and lowering means to move it from'operative to inoperative position.

Having thus described my invention in certain exemplary embodiments, and with the understanding that modifications may be made therein without departing from its spirit and purpose, what I desire to secure and protect by Letters Patent is;

1; In a hopper car having a body the bottom of which comprises a discharge opening closed by a series of hopper doors arranged in opposing pairs hingedly se cured to door supporting members extending between the opposite sides of said discharge opening, the hopper doors in each such opposing pair being movable in opposite directions from a fully opening position in which the said hopper doors hang downwardly to a closed- ,position in which the said hopper doors swing upwardly away from each other so as to close the portion of the discharge opening covered thereby, door actuating means operative to move the pairs of doors from the open to the closed position, to lock the pairs of doors in the closed position and, upon unlocking movement, to release the pairs of doors so that they will drop to the fully open position, said actuating means comprising a series of locking units mounted between the opposing doors in each such pair of hopper doors, saidlocking units each comprising a rock shaft ,extending lengthwise between the opposing doors, a bell crank fixedly mounted on the rock shaft with its opposite ends extending toward the opposing hopper doors, rigid-links pivoted to the ends of said bell crank, the opposite ends of'said links being pivotally connected to;the opposing doors, said bell crank being movableby said rock shaft froma fully closed position in which said links, bias the opposing doors to their closed position, to an open position in which said links release said opposing doors for opening movement, stop means positioned to contact an .arm of said bell crank to establish the fully closed position of the bell crank, in which position the bell crank and links lie in beyond dead center relation and the opposing doors are locked closed, and rock shaft actuating means operatively connected to each of said'rock shafts, said rock shaft actuating means being movable in opposite directions and including linkage means op erative when said rock shaft actuating means is moved in one direction to rotate said rock'shaft so as to move the bell cranks from their open to their fully closed beyond dead center position and, when said rock shaft actuating means is moved in the opposite direction, to

rotate the rock shafts in their opposite direction suf- "ficiently to return said bell cranks and links from their beyond dead center position, whereupon the rock shafts are free to rotate under the influence of the bell cranks and links as the opposing pairs of doors are released for opening movement. 7

2. The hopper car construction claimed in claim 1' wherein said rock shaft actuating means comprises an actuating bar extending lengthwise of said car, wherein each of said rock shafts mounts a lever arm the free end of which is connected to said actuating bar by means of said linkage means, said actuating bar being axially movable to effect movement of said rock shafts.

3. The hopper car construction claimed in claim 2 wherein said linkage means comprises link members interconnecting said actuating bar and each of said rock shaft lever arms, each of said link members having an elongated slot therein which slidably receives the free end of the rock shaft lever arm to which it is attached, whereby said link members maybe moved an appreciable distance by said actuating bar before effecting movement of said rock shaft lever arms, thereby permitting relative adjustment between'the rock shaft actuating means and each of the rock shafts so that said rock shafts, may be sequentially actuated to initiate opening movement of the opposing pair sof hopper doors.

4. The hopper car construction claimed in claim 3 twherein each of said rock shaft lever arms has a shoulder, wherein a displaceable stop overlies each of said shoulders when said locking units are in the fully closed position, whereby said rock shafts are effectively held against opening movement, and wherein said actuating bar mounts stop engaging means operative, upon axial movement of said actuating bar in the direction to effect opening movement of said doors, to displace said stop members and thereby release said rock shaft lever arms for movement under the influence of said linkage means.

References Cited by the Examiner UNITED STATES PATENTS LEO QUACKENBUSH, Primary Examiner. 

1. IN A HOPPER CAR HAVING A BODY THE BOTTOM OF WHICH COMPRISES A DISCHARGE OPENING CLOSED BY A SERIES OF HOPPER DOOR ARRANGED IN OPPOSING PAIRS HINGEDLY SECURED TO DOOR SUPPORTING MEMBERS EXTENDING BETWEN THE OPPOSITE ENDS OF SAID DISCHARGE OPENING, THE HOPPER DOORS IN EACH OPPOSING PAIR BEING MOVABLE IN OPPOSITE DIRECTIONS FROM A FULLY OPENING POSITION IN WHICH THE SAID HOPPER DOORS HANG DOWNWARDLY TO A CLOSED POSITION IN WHICH THE SAID HOPPER DOORS SWING UPWARDLY AWAY FROM EACH OTHER SO AS TO CLOSE THE PORTION OF THE DISCHARGE OPENING COVERED THEREBY, DOOR ACTUATING MEANS OPERATIVE TO MOVE THE PAIRS OF DOORS FROM THE OPEN TO THE CLOSED POSITION, TO LOCK THE PAIRS OF DOORS IN THE CLOSED POSITION AND, UPON UNLOCKING MOVEMENT, TO RELEASE THE PAIRS OF DOORS SO THAT THEY WILL DROP TO THE FULLY OPEN POSITION, SAID ACTUATING MEANS COMPRISING A SERIES OF LOCKING UNITS MOUNTED BETWEEN THE OPPOSING DOORS IN EACH PAIR OF HOPPER DOORS, SAID LOCKING UNITS EACH COMPRISING A ROCK SHAFT EXTENDING LENGTHWISE BETWEEN THE OPPOSING DOORS, A BELL CRANK FIXEDLY MOUNTED ON THE ROCK SHAFT WITH ITS OPPOSITE ENDS EXTENDING TOWARD THE OPPOSING HOPPER DOORS, RIGID LINKS PIVOTED TO THE ENDS OF SAID BELL CRANK, THE OPPOSITE ENDS OF SAID LINKS BEING PIVOTALLY CONNECTED TO THE OPPOSING DOORS, SAID BELL CRANK BEING MOVABLE BY SAID ROCK SHAFT FROM A FULLY CLOSED POSITION IN WHCIH SAID LINKS BIAS THE OPPOSING DOORS TO THEIR CLOSED POSITION, TO AN OPEN POSITION IN WHICH SAID LINKS RELEASE SAID OPPOSING DOORS FOR OPENING MOVEMENT, STOP MEANS POSITIONED TO CONTACT AN ARM OF SAID BELL CRANK TO ESTABLISH THE FULLY CLOSED POSITION OF THE BELL CRANK, IN WHICH POSITION THE BELL CRANK AND LINKS LIE IN BEYOND DEAD CENTER RELATION AND THE OPPOSING DOORS ARE LOCKED CLOSED, AND ROCK SHAFT ACTUATING MEANS OPERATIVELY CONNECTED TO EACH OF SAID ROCK SHAFTS, SAID ROCK SHAFT ACTUATING MEANS BEING MOVABLE IN OPPOSITE DIRECTIONS AND INCLUDING LINKAGE MEANS OPERATIVE WHEN SAID ROCK SHAFT ACTUATING MEANS IS MOVED IN ONE DIRECTION TO ROTATE SAID ROCK SHAFT SO AS TO MOVE THE BELL CRANKS FROM THEIR OPEN TO THEIR FULLY CLOSED BEYOND DEAD CENTER POSITION AND, WHEN SAID ROCK SHAFT ACTUATING MENS IS MOVED IN THE OPPOSITE DIRECTION, TO ROTATE THE ROCK SHAFTS IN THEIR OPPOSITE DIRECTION SUFFICIENTLY TO RETURN SAID BELL CRANKS AND LINKS FROM THEIR BEYOND DEAD CENTER POSITION, WHEREUPON THE ROCK SHAFTS ARE FREE TO ROTATE UNDER THE INFLUENCE OF THE BELL CRANKS AND LINKS AS THE OPPOSING PAIRS OF DOORS ARE RELEASED FOR OPPOSING MOVEMENT. 